1. Field of the Invention
This invention relates to a tool for uniformly paring the end of a tube and, more particularly, for removing burrs from and otherwise finishing the tube end so that it has a uniform cross section.
2. Description of the Prior Art
In order to complete the manufacture of a wide variety of devices, it is commonly necessary to fasten the end of a tube to an annular fitting to provide for fluid communication between the tube and the fitting. Where the connection must be fluid tight, and especially where the fluid is under high pressure, the tube end must be finished so that it mates tightly with the annular fitting. Finishing the tube end removes burrs, pares the end so that it has a uniform cross section and, if desired, creates a chamfer.
The prior art for tube end finishing is comprised primarily of a tool having a cutting edge mounted on a rotary driver. The rotary driver rotates the cutting edge about an axis of rotation. The tube having an end to be finished is rigidly mounted so that its centerline lies colinear with the axis of rotation of the rotary driver and its end is in contact with the cutting edge. The position of the cutting edge on the rotary driver can be changed to vary the location of the cutting edge relative to the axis of rotation.
The tool operator manually positions the cutting edge based on the diameter, thickness and cross section of the tube end and, if called for, the desired chamfer. The operator adjusts the position of the cutting edge on successive trial runs until it appears to him that the cutting edge is in a position that will pare the tube end to the required specification. All tube ends having the same diameter, wall thickness, cross section and requiring the same chamfer are then finished.
The trial and adjustment process is repeated for the next tube or series of tubes having a different diameter, wall thickness, longitudinal cross section or requiring a different chamfer. The process must also be repeated when the cutting edge becomes dull and needs to be removed from the rotary driver to be sharpened or replaced.
The trial and adjustment process is time consuming and, as it must be repeated quite often, the tool operator easily spends more of his time attempting to obtain the proper positioning of the cutting edge relative to the rotary driver and tube end than he actually spends in paring the tube end. The sections of the tube used for trial runs must be scrapped. Further, whether each tube end meets the final chamfer and other finish specifications is determined solely by the personal judgment of the operator, and thus the finished tube ends cannot be guaranted to fall within design tolerances with any degree of certainty.